A toner container that is provided with a lid which opens and closes for the supply of toner has hitherto been housed in toner cartridges for printers and copiers, with the toner being supplied whenever the lid opens and closes.
For example, JP-A 2011-64930 (Patent Document 1) discloses a toner cartridge (process cartridge) equipped with a bottle-like toner container (toner bottle). As shown in FIGS. 1 to 3, this toner bottle has, disposed in a freely rotatable manner within an outer cylinder 3, a bottle body 2 having a lid 1 that can be opened and closed. The toner bottle, by rotation of the bottle body 2 within the outer cylinder 3, feeds a predetermined amount of toner t at a given timing from within the bottle body 2 to a developing unit.
That is, the bottle body 2, which is rotatably disposed within and substantially concentric to the outer cylinder 3, has provided, in part of a peripheral wall thereof, an opening 4 for discharging toner. The opening 4 is arranged so as to be opened and closed by the lid 1 attached to the bottle body 2. The lid 1 swings in the manner of a flap, opening and closing the opening 4. At the time of such closure, a peripheral edge of the lid 1 comes into contact with a sealing member 5 attached to the outer periphery of the bottle body 2, preventing leakage of the toner.
Toner supply from this toner bottle is carried out as follows.
Referring to FIG. 1, normally, an outer surface at a tip of the lid 1 is in contact with an inner peripheral surface of the outer cylinder 3 and thereby pressed in a closing direction, and a peripheral edge on an inner surface of the lid 1 is in pressing contact with the sealing member 5, placing the opening 4 in the bottle body 2 is a powder-tightly closed state. From this state, the bottle body 2 rotates counterclockwise in the diagram (in the direction of the arrow) along with a developing operation by a copier or the like and, with the lid 1 in a state that blocks the opening 4 in the bottle body 2, the outer surface at the tip of the lid 1 slides over the inner peripheral surface of the outer cylinder 3. As shown in FIG. 2, when the tip of the lid 1 reaches a toner outlet 6 provided in the outer cylinder 3, the restrained state at the tip of the lid 1 due to the inner peripheral surface of the outer cylinder 3 is released and the lid 1 opens, allowing toner t to pass successively from the bottle body 2 through the opening 4 and between the lid 1 and the sealing member 5 and be discharged from the toner outlet 6 in the outer cylinder 3, so that a predetermined amount of the toner t is supplied to the developing unit. The bottle body 2 then rotates further and, as shown in FIG. 3, the tip of the lid 1 passes beyond the toner outlet 6, whereupon the tip of the lid 1 is again pressed in the closing direction by the inner peripheral surface of the outer cylinder 3 and the peripheral edge on the inner surface of the lid 1 comes into pressing contact with the sealing member 5, placing the opening 4 in the bottle body 2 in a powder-tightly closed state.
Such a toner bottle is constructed so as to discharge and supply the toner t while the bottle body 2 holding the toner t rotates, and so the toner t within the bottle body 2 is constantly being uniformly leveled as it flows, enabling the toner t to be reliably discharged and supplied in a fixed amount at a time. However, because the toner t constantly flows with rotation of the bottle body 2, leakage of the toner t between the lid 1 and the opening 4 tends to arise. To prevent such toner leakage, it is necessary to reliably maintain powder tightness between the sealing member 5 and the lid 1. The lid 1 and the sealing member 5 repeatedly come into close contact and separate due to the opening and closing action, with compression, release and rubbing of the sealing member 5 recurring each time. As a result, the performance of the sealing member 5 is very important for reliably preventing toner t leakage over a long period of time.
Up until now, elastic members having a base made of an elastic material such as polyurethane foam and, formed on the surface thereof, a rein coating layer to impart slideability have been used as such sealing members. For example, Patent Document 2 (JP-A 2002-214895) describes a sealing member which has a polyurethane foam base and also has a resin coating layer obtained by mixing a low-friction powder such as a fluoropolymer powder or a silicone resin powder together with a resin coating made of acrylic resin, urethane resin, silicone resin or the like and applying the mixture onto the surface of the base.
However, in the coating composition that forms the coating layer, the balance between film formability and coefficient of friction fluctuates greatly depending on the combination and content ratio of the base resin and the low-friction powder, making it difficult to form a coating layer that is suitable as the surface layer of a sealing member. Hence, it is currently not always possible to obtain a sealing member having a fully satisfactory performance.